No. All the solid tools are the basic boolean operations. There is no native "fix" tool for poor solid modeling.
But there are some 3rd party extensions to help inspect your "solids". ThomThom's Solid Inspector is one.
Keep in mind SketchUp is a surface modeler, not a true solid modeler. So it's object's are always "hollow". SketchUp considers "hollows" closed by surfaces (as described by Dave above,) to be "manifold solids" if they are grouped or made a component instance.
The STL Exporter extension requires the object to be a single level manifold group (I believe.) Ie, no sub-groups nor component instances.